Finally we have assumed a global intervention on envelopes - shown in Fig. 11 - for which it confirms a payback period of investments contained within the life of the building, without considering indirect benefits, unquantifiable with sufficient reliability for the perceptual formal aspects, as well as the improvement of safety levels and indoor comfort for buildings' users [1,14,15]. Moreover, the analysis does not consider the cases in which the intervention on envelopes take priority, regardless of instant economic convenience, because the serious conditions of inefficiency and degradation of the closures and the frames, often characterized by pathologies that render the indoor environmental conditions inadmissible and unsustainable for the users [16-18].
As a results of the previous analysis, it have been considered a
mean cost of the intervention as follows: